TCP/IP will never go mainstream. It is just a prototype. The idea that a protocol that was state of the art in the 1970s will be used by billions of people in the 2010s is just stupid. By 1979 the internet hadn't become mainstream so obviously it was never going to happen. Something more efficient than the internet will come along and we will use that instead.
Let's be honest, TCP/IP shouldn't be what we use. Since the government held a monopoly on the early Internet for the first half of the Internet's existence they got to embed whatever they thought worked best instead of what actually worked best.
That said, I think Bitcoin is so revolutionary that no one is going to line up to build a second crypto infrastructure for a competitor coin anytime soon.